/*
 * jPOS Project [http://jpos.org]
 * Copyright (C) 2000-2015 Alejandro P. Revilla
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package org.jpos.iso;

import java.io.IOException;
import java.io.InputStream;

/**
 * Similar to Europay format, but instead of LLTT it's TTTTLLL
 * <code>
 * Format TTLL....
 * Where
 * TTTT is the 4 digit field number (Tag)
 * LLL is the 3 digit field length
 * .. is the field content
 * </code>
 *
 * @author Alejandro Revilla
 * @version $Id$
 * @see IFEP_LLCHAR
 */
public class IFIPM_LLLCHAR extends ISOFieldPackager {
	public IFIPM_LLLCHAR() {
		super();
	}

	/**
	 * @param len         - field len
	 * @param description symbolic descrption
	 */
	public IFIPM_LLLCHAR(int len, String description) {
		super(len, description);
	}

	/**
	 * @param c - a component
	 * @return packed component
	 * @throws ISOException
	 */
	public byte[] pack(ISOComponent c) throws ISOException {
		int len;
		String s = (String) c.getValue();

		if ((len = s.length()) > getLength() || len > 997)   // paranoia settings
			throw new ISOException(
					"invalid len " + len + " packing IFIPM_LLLCHAR field "
							+ c.getKey() + " maxlen=" + getLength()
			);

		return (
				ISOUtil.zeropad(c.getKey().toString(), 4)
						+ ISOUtil.zeropad(Integer.toString(len), 3)
						+ s
		).getBytes();
	}

	/**
	 * @param c      - the Component to unpack
	 * @param b      - binary image
	 * @param offset - starting offset within the binary image
	 * @return consumed bytes
	 * @throws ISOException
	 */
	public int unpack(ISOComponent c, byte[] b, int offset)
			throws ISOException {
		if (!(c instanceof ISOField))
			throw new ISOException
					(c.getClass().getName() + " is not an ISOField");

		c.setFieldNumber(
				Integer.parseInt(new String(b, offset, 4))
		);
		offset += 4;
		int len = Integer.parseInt(new String(b, offset, 3));
		offset += 3;
		c.setValue(new String(b, offset, len));
		return len + 7;
	}

	public void unpack(ISOComponent c, InputStream in)
			throws IOException, ISOException {

		if (!(c instanceof ISOField))
			throw new ISOException
					(c.getClass().getName() + " is not an ISOField");

		int fldno = Integer.parseInt(new String(readBytes(in, 4)));
		int len = Integer.parseInt(new String(readBytes(in, 3)));
		c.setFieldNumber(fldno);
		c.setValue(new String(readBytes(in, len)));
	}

	public int getMaxPackedLength() {
		return getLength() + 7;
	}
}

